Production of esters



Patented Feb. 25, 1936 UNITED STATES PATENT OFFICE.

PRODUCTION or ES'IEBS Heinrich Bertsch, Chemlnitz, Germany, assignor .to H. Th. Biihme Aktiengesellschaft, Chemnitz, Germany, a corporation of Germany No Drawing. Application January 29, 1930, Serial No. 424,456. In Germany February 6, 1929 15 Claims. (01. zed-99.12)

Said process consists in first producing the esters of the carboxylic acidswith alcohol radicals having a low carbon number (say up to cetyl alcohol) and then sulphonating said esters. The result of this process was that in the sulphonating step not only did sulphonation of the esters take place but also the alkyl or aryl radical attached to thecarboxyl group passed wholly or in part to the sulphuric acid radical group so that the end product consisted of esters of the sulpho-fatty acids, possibly inadmixture with carboxylic acid esters or with esters in which both the sulphuric acid radical and carboxyl group were esterified.

'One object of this invention is to'provide alternative means for arriving at the results described. Accordin to one feature of this invention the above reaction can be performed even more smoothly if an intensive sulphonating and sulphating agent is caused to act upon the lower carboxylic acid esters. Such an agent may be a sulphonating agent the effects of which have been improved by appropriate additions or may be a sulphonating agent which by itself acts very energetically. Furthermore such improvingad- 'ditions may also be made to sulphonating agents which are already energetic by themselves. The temperature is preferably kept below 15 C. whereby saponiflcation of the esters to be sulphonated is avoided or confined to avery small amount and the yield is correspondingly im- -proved. As energetic sulphonating agents usev may for instance be made of fuming sulphuric acid, sulphur trioxide (preferably in vapour form or as high percentage oleum) or chloro-sulphonic acid. Mixtures of concentrated sulphuric acid, or 'of the sulphonating agents just mentioned, with anhydrous lower fatty acids, their anhydrides or chlorides, for example mixturesof fuming sulphuric acid with acetic anhydride may also be employed. Alternatively the sulphonating agents may be allowed to react with the lower fatty acids or theirderivatives and the resultant products, for instance acetyl sulphuric acid, caused to act, eitheralone or in mixture with sulphuric acid or the like, upon the carboxylic acid esters. Finally also,.alkyl derivatives of sulphuric acid or chloro-sulphonlc acid may be used alone or in admixture with other sulphonating agents. By such means products are obtained which, for the greatest part, are esterified both in the sulpho-group and in the carboxyl group.

- Example 1 kgs. of oleum having a 30% sulphur trioxide content are gradually added over a period of several hours to kgs. of ricinoleic acid -nbutyl ester, maintained at a temperature below 5 C. during which time the mass is vigorously stirred. The stirring is continued for an hour or so after the addition has been completed. To the crude sulphonation product there is added an equal amount byweight of crushed ice. The mass is stirred thoroughly, allowed to settle until a film forms and the collected dilute acid poured off. The oily product is then agitated with Giaubers salt solution and again allowed to settle whereupon the salt solution is separated. The oil can then be neutralized with soda liquor if so desired. So far as is known, the structure of the product may be represented by the following formula:

0H3-wmncncmcn-cm-(crap-000cm,

soar soar! Example 2 In a similar manner 100 kgs. of ricinoleic acid methyl cyclohexanol ester are sulphonated, at a 100 kgs. of oleic acid benzyi ester are sulphonated with 100 kgs. of oleum (10% 50:). The preparation is continued as in Example 1. So far as is known, the structure of the product may be represented by the following formula:

cumin)1-c cH,-(cHm'coo-om-cim 300 "Example 4 g 100 kgs. of ricinoleic acid-iso-butyl ester are sulphonated with 100 kgs. of oleum (10% $03) in the presence of 100 kgs. of acetic anhydrlde.

' The preparation is continued-as in Example 1.

' "mixture.

So far as is known, the structure of the product may be represented by the following formula:

cmormtcH-cmcHm-cooclm Example 5 penetrating, foaming, dispersion and like agents.

So far as is known, the structure of the product may be represented by the following formula:

SOaH According to a further feature of this invention said esters may also be obtained in good yields direct from the carboxylic acids, without concomitant reactions causing disturbance to any material extent, if the intensive or ener-' getic sulphonating agents are caused to act upon the carboxylic acids themselves and the alcohol, with which a, carboxylic acid or sulpho acid, is to be esterifled, is added to one of the reaction components or to the reaction mixture before, during or after] the sulphonation. As already pointed out these intensive or energetic sulphonating agents are substances such as fuming sulphuric acid, sulphur trioxide (preferably in vapour form or as high percentage oleum) and chloro-sulphonic acidor mixtures of concentrated sulphuric acid, or of the sulphonating agents just referred to, with anhydrous lower fatty acids, their anhydrides or chlorides.

The process may for example, be carried into effect by treating an appropriate carboxylic acid of high molecular weight with one of the sulphonating agentsor mixtures referred to and adding the appropriate alcohol to the raw sulphonation product. Alternatively the alcohol may be mixed with the carboxylic acid and the sulphonating agent then caused to act upon the Alternatively again it is possible"to work direct with the appropriate alkyl sulphuric acid or alkyl sulpho-chloride. Preferably a temperature below 15 C. is adhered to during the sulphonation.

It will be observed that this application deals 66 chiefly with the treatment of unsaturated and hydroxy fatty acids and their esters, but unsaturated acids as described herein are to be understood as including those which contain aromatic nuclei.

Example 6- 100 kgs. of ricinoleic fatty acid are sulphonated with kgs. of oleum (30% $03) at a temperature below 5 C. 25 kgs. of iso-butyl alcohol are added to the raw sulphonation product during stirring which is continued for several-hours. After the reaction has ended, ice is added and the reaction productis washed withGlaubers salt solution. The structural formula is similar to that of Example 1.

Example 7 kgs. of. 12-hydroxy-stearic acid are mixed with 50 kgs. of butyl alcohol and sulphonated at a temperature below 0 C. with 36 kgs. of chlorosulphonic acid. After the reaction has ended. the preparation is'continued as in Example 6. So far as is known, the structure of the product may be represented by the following formula:

' KCEh-QH-(Clishe-COOGiH; 55033 I Example 3 In place of acetic anhydride, an equivalent amount of acetyl sulphuric acid may be used and the quantity of oleum added may, if desired,

be reduced accordingly.

Example 9 100 kgs. of naphthoic acid are sulphonated with 70 kgs. of chloro-sulphonic acid. 35 kgs. of iso-propyl alcohol are added to the crude sulphonation product. The preparation is continued as in Example 6. The structural formula is similar to that of Example 5.

Erample 10 48 kgs. of butyl sulphuric acid are added to 100 kgs. of ricinoleic fatty acid at a temperature be-v low 15 C. The preparation is continued as in Example 1.

Butyl sulphuric acid may be replaced by the equivalent amount of butyl sulphuric acid chloride.

While the term sulphonation is used throughout the specification and claims to describethe principal reaction, it is recognized in the art to which this invention relates that reactions of this character may result either in the formation of true sulphonic acids or sulphuric acid esters, or both, depending upon the conditions and the materials which enter into the reaction.

For instance, in carrying out the process in the manner set forth in Examples 2, 7, and 10, sulphuric acid esters or sulphates are principally formed; in the reaction conducted in accordance with Examples 1, 3-6, and 8, mixtures of fatty sulphuric acid esters with fatty sulpho acids are formed; while in Example 9 aromatic sulpho acids are produced. It is therefore understood that the terms sulphonation and "sulphonation product" are used generically and are intended to cover the reaction and the reaction product resulting from the use of any well known sulphating and sulphonating agent.

- The principal reactions of the processes outlined in this application are believed to be properly represented by the following equations. (1) Starting material: Unsaturated fatty acid+alcoho1'.

0m, soar (11) Starting material; Oxy-fatty acid+alcohol.

" ing agent and esterifying said carboxylic acid with a monohydroxy alcohol, the sulphonation 111) Starting material: Completely formed alkyl esters of an unsaturated fatty acid.

and sulphation being efiected in the presence of an anhydrous lower fatty acid radical compound OSOaH In neutralizing. with NaOH the acetic acid residue is split off and the following is formed:

CHa-(CHz)1-CHCH-(CHzhCOOC4HH-CHiCOONa BOZNB (IV) Starting material: Completely formed alkyl esters of an oxy-fatty acid.

selected from the group consisting of lower fatty acids. their anhydrides and chlorides.

'7. The process of producing esters of sulphonated carboxylic acids comprising reacting a carboxylic acid having not less than 10 carbon atoms and selected from the group consisting of unsaturated and hydroxy fatty acids, a monohydric alcohol and an intensive sulphonating nated carboxylic acids comprising reacting a carboxylic acid having not less than 10 carbon atoms and selected from the group consisting of unsaturated and hydroxy fatty acids, and a monohydroxy alcohol different-from phenol having less than 16 carbon atoms and an intensive sulphonating agent at a temperature less than 15 C.

3. The process of producing esters of sulphonated carboxylic acids comprising reacting a carboxylic acid having not less than 10 carbon atoms and selected from the group consisting of unsaturated and hydroxy fatty acids with an intensive sulphonating agent at a temperature less than 15 C. I and esterifying the sulphonated product obtained with a monohydric alcohol.

4. The process .of producing esters of sulphonated carboxylic acids comprising reacting a carboxylic acid having not less than 10 carbon atoms and selected from the group consisting of unsaturated and hydroxy fatty acids with an intensive sulphonating agent at a temperature less than 15 C. and simultaneously esterifying with a monohydric alcohol.

5. A process in accordance with claim 1 wherein the sulphonatin'g agent is selected from-the group consisting of fuming sulphuric acid, sulphur trioxide and chlorosulphonic acid.

6. The process of producing esters of sulpho nated carboxylic acids. comprising sulphonating and sulphating a carbowlic acid having not less than 10 carbon atoms and selected from the group consisting .of unsaturated and hydroxy fatty acids by means of an intensive sulphonat agent, the sulphonation being efiected in the presence of an anhydrous lower fatty acid compound selected from the group consistingof lower fatty acids, their anhydrides and chlorides.

8. The process of producing ,esters of sulphonated carboxylicacids comprising reacting a carboxylic acid having not less than 10 carbon atoms and selected from the group consisting of unsaturated and hydroxy fatty acids with an intensive sulphonating agent at a temperature below 15 C. and esterifying with a monohydric alcohol of low molecular weight.

9. The process of producing sulphonated carboxylic acids esterified with monovalent alcohol radicals of low molecular weight diiferent from phenol comprising reacting a carboxylic acid having not less than 10 carbon atoms and selected from the group consisting of unsaturated and hydroxy fatty acids, an intensive sulphonating agent and a monohydric alcohol radical containing compound at a temperature less than 15 C. 10. In the process of sulphating and sulphonating completely formed alkyl esters of unsaturated and hydroxy carboxylic acids having not less than 10 carbon atoms by the reaction therewith of a sulphonating agent, the step which comprises introducing in the reaction mixture a sulphonation promotion medium comprising an anhydrous lower fatty acid radical compound.

11. In the process of sulphating and sulphonating completely formed alkyl esters of unsaturated and hydroxy carboxylic acids having not less than 10 carbon atoms by the reaction therewith of a sulphonating agent, the step which comprises introducing in the reaction mixture a sulphonation promotion medium comprising an anhydrous lower fatty acid radical compound, said compound being selected from the group consisting of lower fatty acids, their anhydrides,,and chlorides.

- 12. In the processor sulphating and sulphonating completely formed alkyl ester's'fof unsaturated and hydroxy carboxylic acids having not less than 10 carbon-atoms by the reaction therewith of a sulphonating agent, the step which comprises introducing in the reaction mixture a sulphonation promotionmedium comprising ace- 13. The process set forth in claim 10 in which the ester is derived from ricinoleic acid.

14. In the process of sulphating and sulphunating completely formed alkyl esters of unsaturated and hydroiw carbo xylic acids having not less than 10 carbon atoms by the reaction therewith of a sulphonating agent, the step which comprises introducing in the reaction mixture 9.

sulphonatlon promotion medium comprising an anhydrous lower fatty acid radical compound, at a. temperature below 15 C.

15. The process of forming esters of sulpho acids which comprises reacting a butyl ester of ricinoleic acid with an energetically acting sulphonating' and sulphating medium. I

' HEINRICH BERTSCH. 

